clean up minor compiler warnings (#79)

set c99 on tests/CMakeLists.txt

src/codecs/jtencode/lib/init_rs_int.cpp

@@ -30,7 +30,7 @@ void * JTEncode::init_rs_int(int symsize, int gfpoly, int fcr, int prim,
 
   rs = ((struct rs *)0);
   /* Check parameter ranges */
-  if(symsize < 0 || symsize > 8*sizeof(data_t)){
+  if(symsize < 0 || (unsigned) symsize > 8*sizeof(data_t)){
     goto done;
   }
 

src/drivers/si4063/si4063.c

@@ -684,7 +684,9 @@ int si4063_init()
 
 void TIM1_BRK_TIM15_IRQHandler(void)
 {
+#ifdef DFM17
     static bool pin_state = false;
+#endif
 
     if (TIM_GetITStatus(TIM15, TIM_IT_Update) != RESET) {
         TIM_ClearITPendingBit(TIM15, TIM_IT_Update);

tests/CMakeLists.txt

@@ -7,6 +7,8 @@ project(RS41ng_test C CXX)
 
 set(BINARY ${CMAKE_PROJECT_NAME})
 
+SET(CMAKE_C_FLAGS "${COMMON_FLAGS} -std=gnu99")
+
 file(GLOB_RECURSE USER_SOURCES "../src/config.c" "../src/codecs/*.c" "../src/template.c" "../src/utils.c" "../src/strlcpy.c")
 file(GLOB_RECURSE USER_SOURCES_CXX "../src/codecs/*.cpp")
 file(GLOB_RECURSE USER_HEADERS "../src/codecs/*.h" "../src/template.h" "../src/utils.h" "../src/config.h" "../src/strlcpy.h")